What are ticks?

Ticks look like flat little spiders. They are found all over the country in forests, dunes, heaths, sheltered meadows, parks and gardens. Ticks feed on the blood of animals, and sometimes humans. They can remain attached to the skin for hours or even days without being noticed, filling up with blood. Tick bites are usually harmless. However, it is still important to remove a tick as quickly as possible. This is because ticks may carry the Borrelia burgdorferi bacterium and could transmit Lyme disease.

How do ticks bite humans?

Ticks move from grasses and shrubs to animals and humans. Once they have found a host, they will look for a suitable place to bite into the surface of the skin. In humans, the ideal spots are the groin and buttocks, the backs of the knees, armpits, along the underwear, behind the ears, and around the hairline at the neck (especially in children).

How can ticks transmit Lyme disease?

The lifecycle of a tick goes through four stages: egg, larva, nymph, and adult. Ticks need blood during those last three stages. They look for an animal or human host to provide that blood. If the host (such as a small rodent or bird) carries the bacterium that causes Lyme disease (Borrelia burgdorferi), the tick can become infected. After eating the blood it needs, the tick will drop off and live on the ground between grasses and leaves. There, it prepares for its next life stage. Infected ticks carry the Borrelia bacterium. After several months, the tick will look for its next host and a new meal of blood. When the tick feeds again, it can infect the host.

Nymphs and adult female ticks are particularly likely to carry Lyme disease. The adult female tick lays her eggs when she is full of blood. After that, she dies.

How can you recognise a tick?

Ticks are very small, only 1 to 3 millimetres. They are easy to miss. If you have been bitten by a tick, at first it will look like a small black dot on your skin. Once they bite, ticks start drinking blood. After several days, they swell up to a brown or grey ball the size of a pea.

Where do ticks live?

Ticks are found all over the country in forests, dunes, heaths, sheltered meadows, parks and gardens. They mostly live in tall grass or decomposing leaves, ideally near trees or bushes. From there, they will wait for passing animals or humans to climb onto. Ticks do not fall from trees.

When are ticks active?

There are ticks all year round. As soon as the temperature rises above 7°C, they can become active. Most tick bites occur in the months of March through October.

How common are tick bites?

Every year, over 1 million people get bitten by a tick.

How many ticks in the Netherlands carry the bacterium that causes Lyme disease?

This strongly depends on the area, vegetation, number of infected rodents, and tick population density. In the Netherlands, about one in every five ticks (20%) carries the bacterium that can cause Lyme disease (Borrelia burgdorferi).

How can you protect yourself?

Ticks are mostly found in high, shaded grass and decomposing leaves near trees and bushes. That is why it is important to check for tick bites after visiting such places.

Can I take extra precautions?

People who often come into contact with ticks (such as foresters, gardeners and military personnel) are advised to protect themselves against tick bites by taking the following precautions:

• Keep to the paths as much as possible and try to avoid dense vegetation and bushes.
• Wear closed shoes, long sleeves and trousers. Tuck the legs of your trousers into your socks. Tip: Ticks are easier to spot on light-coloured clothing.
• Wear clothing that has been treated with Permithrin insect repellent, or spray your clothing with a bug spray containing DEET (diethyltoluamide).
• Apply a product containing DEET to bare skin.

These precautions offer no guarantee that you will not be bitten by a tick. It is still important to check your body and clothing for ticks after visiting green areas.

How do I check for ticks?

Have you visited a place where ticks are likely to be found? Check yourself and others for ticks. Ticks prefer specific areas on the human body: groin and buttocks, the backs of your knees, armpits, along your underwear, behind your ears, and around the hairline at your neck. Use a mirror or magnifying glass if needed. Remember to check your clothing. You can wash clothing with ticks at 60ºC for at least 30 minutes or wash the clothes and then put them in the dryer. This will kill any ticks.

What should I do if I have a tick bite?

• Always remove the tick as soon as possible! The longer the tick is attached to your skin, the higher the risk that it will transmit diseases. 
• Do not use alcohol, iodine, oil, soap or any other substance before removing the tick.
• Use pointed tweezers to grasp the tick’s head as closely as possible to the skin and gently pull it out. A small piece of the head that is left behind is nothing to worry about. It will fall out on its own, just like a splinter. Only after removing the tick, disinfect the bite wound with 70% alcohol or iodine. Are you using a different type of tick remover? Follow the instructions that came with it. If necessary, you can use a magnifying glass.
• Make a note of the date and the place on your body where you were bitten.

What should I look out for after a tick bite?

Lyme disease can cause the following symptoms:

• Expanding discolouration of the skin at the location of the tick bite. This ‘ring’ around that spot can appear for up to three months after a tick bite.
• Fever, possibly accompanied by muscle ache and joint pain, in the first weeks after the bite. 
• Joint problems, skin conditions, nervous complaints or cardiac symptoms may sometimes develop. This can occur if early symptoms of Lyme disease were not treated with antibiotics. However, these symptoms may also be the first signs of the disease.

Both the early and the later stages can be treated with antibiotics. However, if it progresses to a later stage, the infection may have already caused damage. For that reason, it is important to contact your GP if you have these symptoms.

What can I use to remove a tick?

It is important that you use a tool that allows you to grasp the tick’s head firmly. You can use pointed tweezers or other tick removers. They are sold by drugstores and chemists.
The main thing is to remove the tick quickly. If the tick has only just attached itself to the skin (if it is still small and flat and not full of blood) and it will be a while before you can access a tick remover, you could also pull it out with your nails. If you are going to a green area, it is better to bring a tick remover in case you need it.

What does it mean if I have a small red spot on my skin after a tick bite?

A small red spot at the bite location in the first few days is a normal skin reaction. If the spot does not expand, and disappears within a few days, it is very unlikely that it is a symptom of Lyme disease. Consult your GP if the spot grows larger.

Can ticks in other countries also transmit diseases?

In other countries, ticks may be carrying other diseases in addition to Lyme disease.
For more information, go to the website of the National Coordination Centre for Travellers Advice (LCR).

What should I do after a tick bite in another country?

Whether at home or in a foreign country, it is always important to remove the tick immediately. Make sure you bring a tick remover with you. Then note the following details:

• the date of the tick bite;
• the location on your body where the tick bit you;
• the country and region where you were bitten.
• Always consult a doctor if you develop symptoms, even if you are abroad.

If you go to your GP because you have symptoms, inform them that you were bitten by a tick.

How do you get Lyme disease?

Ticks can transmit Lyme disease if they are infected with the Borrelia burgdorferi bacterium. When the tick drinks blood, the bacteria can be transferred to the host through the tick’s saliva. The tick does not transmit the bacteria as soon as it attaches to its host. The sooner the tick is removed, the lower the risk of the bacterium being transmitted. If the bacterium does enter your body, you may get Lyme disease. Most people do not get ill after a tick bite. There is an estimated 2% risk of getting Lyme disease after a tick bite (2 out of 100 tick bites).

Direct human-to-human transmission does not currently appear to play a significant role (except for vertical transmission). Although transmission via sexual contact, organ donations, or blood transfusions could theoretically be possible in exceptionally rare cases, there is no scientific evidence for this. Similarly, people cannot get infected by removing ticks.

What symptoms are associated with Lyme disease?

The symptoms of Lyme disease can vary greatly. Not everyone develops the same symptoms. Lyme disease can cause the following symptoms:

• Expanding discolouration of the skin at the location of the tick bite. This ‘ring’ around that spot can appear for up to three months after a tick bite.
• Fever, possibly accompanied by muscle ache and joint pain, in the first weeks after the bite.
• Joint problems, skin conditions, nervous complaints or cardiac symptoms may sometimes develop. This can occur if early symptoms of Lyme disease were not treated with antibiotics. However, these symptoms may also be the first signs of the disease.

Both the early and the later stages can be treated with antibiotics. However, if it progresses to a later stage, the infection may have already caused damage. For that reason, it is important to contact your GP if you have these symptoms.

Who is at greater risk of becoming infected?

Anyone can become infected with the Borrelia burgdorferi bacterium from a tick bite and get Lyme disease. People who spend a lot of time in green areas, such as foresters, gardeners and military personnel, have a higher risk of getting a tick bite. There are health and safety protocols that explain how employees can protect themselves from tick bites. Another group with a higher risk of getting tick bites are people who enjoy outdoor recreation (such as hikers and campers) and children (from playing outside).

How high is the risk of getting Lyme disease after a tick bite?

Only ticks that carry the Borrelia bacterium can transmit Lyme disease. Approximately one in every five ticks carries the bacterium that can cause Lyme disease (Borrelia burgdorferi). Infection does not always lead to Lyme disease. The human body’s own defence mechanism is often capable of neutralising the bacterium.

Every year, over 1 million people get bitten by a tick. About 2 in 100 people get Lyme disease after a tick bite: some 27,000 people every year. The nature and severity of symptoms in patients with Lyme disease can vary greatly. The vast majority of people who get Lyme disease develop a characteristic ring or spot at the bite location. 1,200 to 1,500 people a year also develop additional joint problems, skin conditions, nervous complaints, or cardiac symptoms due to Lyme disease. Out of the 27,000 patients, an estimated 1,000 to 2,500 people continue to have persistent symptoms. The Lyme Prospect study is trying to find out why. 

When should I contact my doctor?

Contact your GP if you have any of the following symptoms:

• Discolouration of the skin at the location of the tick bite, which expands gradually. This ‘ring’ around that spot can appear for up to three months after a tick bite.
• Fever, possibly accompanied by muscle ache and joint pain, in the first weeks after the bite.
• Joint problems, skin conditions, nervous complaints or cardiac symptoms may sometimes develop. This can occur if early symptoms of Lyme disease are not treated with antibiotics. However, these symptoms may also be the first signs of the disease.

Both the early and the later stages can be treated with antibiotics. However, if it progresses to a later stage, the infection may have already caused damage. For that reason, it is important to contact your GP if you have symptoms that could indicate Lyme disease.

Can you become immune to Lyme disease?

No, each new tick bite is a new risk of infection.

Is there a vaccine against Lyme disease?

No, there is no vaccine against Lyme disease available at this time.

Does it matter whether the tick drinks lots of or a little bit of blood?

A tick that is very full of blood has been attached to the skin for some time. The longer an infected tick is attached to the skin, the greater the risk that it will transmit the Borrelia bacterium.

Can you have Lyme disease without having observed a red ring or seen a tick bite?

Yes. Not all people with Lyme disease have first observed a red ring. And only a third of the people with Lyme disease actually remember a tick bite.

How is Lyme disease treated?

At an early stage, Lyme disease can be treated very effectively with antibiotics. Your GP can prescribe them. If Lyme disease goes untreated at an early stage, this may lead to joint problems, skin conditions, nervous complaints or cardiac symptoms later on. These later stages can also be treated with antibiotics. However, the infection may have already caused damage.

Does everyone who is infected with the Borrelia bacterium get Lyme disease?

No, not necessarily. The human body’s own defence mechanism is often capable of neutralising the bacterium.

Is it useful to examine a tick?

No. A negative result is no guarantee that the tick was not infected. Moreover, there may have been more ticks that went unnoticed or were not examined. But a positive result does not provide any certainty either. Only a handful of people that are bitten by an infected tick then actually get infected themselves. For now, examining attached ticks only has value in the context of scientific research.

Are any reliable tick tests available?

Various tick tests are available online and from drugstores and chemists, and some commercial laboratories offer tick testing services. These tests are intended to examine if the tick is infected with the Borrelia bacterium.

However, an infected tick does not always lead to Lyme disease – far from it! Testing ticks is only useful if the test can also predict whether or not someone would get Lyme disease. No tests are currently available in the Netherlands that have been clinically validated by independent research.

Is it worth giving employees (people working in green areas) annual tests for Lyme disease?

There is currently no solid evidence to support annual blood tests to check individual employees working in green areas for Lyme disease. The Institute for Healthcare Improvement (CBO) guideline (www.cbo/lyme) and the Lyme Borreliosis guideline for Health and Safety Professionals by the Netherlands Society of Occupational Medicine (NVAB) endorse this (with the exception of any epidemiological research). A positive test only tells you that you were exposed to the bacterium that causes Lyme at some point. Antibiotic treatment for someone who previously encountered Borrelia but is now healthy would be unnecessary and may sometimes have a negative effect because of the potential side-effects of antibiotics. In addition, treatment has not been proven to prevent future development of symptoms. If you are currently experiencing health problems, please contact your GP and do wait for screening or annual testing.